Installation for the production of hot gases under pressure



Oct. 13, 1953' P. E. J. M. MALDAGU'E 2,655,364

INSTALLATION FOR THE PRODUCTION OF HOT GASES UNDER PRESSURE Filed Oct. 51, 1950 2 Sheets-Sheet l Gas/1 am aqua 4M4 I I 7//////1 v v v 14/ vilvrok P/E R 50M alvo JuLEJL M RIEMALDAM 5 By lfrwv- 1953 P. E. J. M. MALDAGUE 2,655,354

INSTALLATION FOR THE PRODUCTION OF HOT GASES UNDER PRESSURE Filed Oct. 51, 1950 2 Sheets-Sheet 2 aprrann/Ey.

Patented Oct. 13, 1953 UNITED STATES PATENT OFFICE INSTALLATION FOR THE PRODUCTION OF HOT GASES UNDER PRESSURE Application October 31, 1950, Serial No. 193,160 In Belgium November 10, 1949 1 Claim.

The present invention relates to installations for the production of hot gases under pressure; for example, for the production of hot blast for blast furnaces.

It is an object of the invention to provide an installation for the production of hot gases under pressure having the advantages of comparably low cost of manufacture and maintenance, and simplicity and flexibility of operation.

The invention comprises the installation of turblues of an identical construction to be used in the individual plants; only the shape and the arrangement of the orifices of the turbines for the inlets and outlets of the gases are differently shaped in conformity with the connecting pipes; also, the compressors may have an identical shape. In this manner, the installation costs of the plants can be greatly reduced.

A characterizing feature of the invention is the application of turbines and compressors of the type used in aviation gas turbines, which have a smaller weight than turbines ordinarily used for the production of the compressed gases for the operation of a blast furnace.

The arrangement of the means for the production of hot and compressed gas in conformity with the invention is illustrated in the attached drawings, in which Fig. 1 is a diagrammatical view of the plant;

Fig. 2 is a longitudinal sectional view of a compressor used for the compression of the gas or of the combustion air;

Fig. 3 is a longitudinal sectional view of a modified compressor used when the fuel employed in the plant is a weak gas; and

Fig. 4 is a diagrammatical view of a plant for use of a weak gas.

The hot compressed gas to be produced in conformity with the invention and hereafter referred to as gas A, for instance the blast of a blast furnace, is sucked in through pipe I at a pressure pl by a compressor CI which discharges it at 2 at a pressure p2 considerably above the pressure p3 and at which it will be used. The gas A leaving the compressor CI is then re-heated in a heater E which it leaves at 3 then in a heater RI which it leaves at 4; the gas A is then expanded from a pressure 112 to a pressure p3 in a gas turbine TI which it leaves at 5 in order to undergo a final re-heating in a heater R2 which it leaves at 6 in order to be used.

The heaters E, RI and R2 are heated by combustion gases flowing in the following circuit; the combustion air is taken in by the compressor 02 at 'I and is discharged at 8; during thisphase,

the compressor C2 increases the atmospheric pressure of the air to a pressure pZ which is about equal to the pressure 102 of the gas A, as above defined. The combustion air leaving the compressor C2 enters the combustion chamber Ch into which liquid or gaseous fuel is entered to produce a combustion gas. The temperature and the pressure of the fuel is raised by the apparatus C3 to a pressure p2.

The combustion gas leaves the combustion chamber Ch, at 9, is cooled in the heat exchanger R2, and leaves at I0; thereafter the combustion gas is further cooled in the heat exchanger RI; it leaves at I I. This cooled gas enters a gas turbine T2, in which it is expanded from pressure p2 to pressure p'3, which is to be about equal to pressure 103. The combustion gases leaving the turbine T2 at I2 are divided into two substantially equal portions. One of these portions is expanded by entering the gas turbine T4 at I4 and departing at I5; the other portion of gas is expanded simultaneously in the gas turbine T3 entering the same at I3 and leaving it at I6.

The turbines T3 and T4 are operated into an expansion, which is about equal to the atmospheric pressure. The combustion gases leaving the turbines T3 and T4 at I5 and I6, respectively, are reunited in order to enter the heat exchanger E at IT; here they are cooled before being finally released into the atmosphere at I8.

The shafts of compressor CI, turbine TI and turbine T3 are coupled, so that their shafts form a first succession of shafts I. The shafts of compressor C2, apparatus C3, turbine T2 and turbine T4 are coupled, so that their shafts form a second succession of shafts II.

The. starting of the plant is commenced with closing valve VI in the pipe line leading to turbine T3. The motor din the succession of shafts II is started; when the shafts in line II reach a sufficient speed, an ignition is caused in the combustion chamber Ch. If the combustion gas enters turbine T2, the starting motor d! is uncoupled, so that now the machines in the line of shafts II operate.

These starting operations maybe effectedin any known manner. The valve VI will be opened, if the shafts in line II have the normal speed and the machines grouped in the successionof shaft I may be started by entering the combustion gas into turbine T3.

The speed regulation of the line of shafts I is controlled by a speed regulator SI which controls a by-pass valve VRI for burnt gases that pass through the heater RI. The opening of this valve causes a reduction in the temperature of the gas A at the inlet to the turbine T l and therefore a reduction in the power supply for this turbine Tl which has the effect of retarding the rotational speed of the line of shafts 1. Conversely theclosingcf the valve VRI causes an acceleration of the rotational speed of the line of shafts I.

Speed regulation of the line of shafts II is effected by a speed regulator S2 which controls the entry of fuel into the combustion chamber Ch. The reduction in the delivery of fuel causes a reduction in the temperature. o-f'the combustion gases at the entrance to the'turbine T2=and therefore a reduction in the power 'supply'for this turbine T2 which has the effect of retarding the rotational speed of the line of shaftsII. Conversely the closing of the valve VRI causes an acceleration of the rotary speed of the line *of shafts II.

Regulation of the gas A at B iseffected by a thermostat S3 that controls a by-pass valve .VR2 ior the combustion gases which passthrough the heater RI. Regulation of the pressure .of the gas A at-6 is effected by a one way-valve V2 that is positioned between the points and I3; this permits to direct towards the turbine T3 a part of the gas A leaving the turbine TI in'the event that an increase of the pressure 16 tends to slow down the speed of the line ofshafts'l.

'Inan installation according to the invention the deliveries by weight of the gas A flowing through the turbine TI :and of "the combustion gas flowing through the turbine T2 are substantially equal under normal conditions of opera- "tion; moreover, the relation of the pressure p2 to the pressure 413 is chosen in such a manner that the volumetric delivery of the combustion gas at the outlet from the turbineTZ willbesub- 'stantially equal to twice the amount of the volumetric delivery of these gases at the'point I I of entry to this turbine. From this results the possibility, when the pressure :03 is about 'two atmospheres, of using a single type of fixed and "movable blades and rotor for the turbines T2,

T3 and T4. Furthermore, if the specific volumes of the gas A-and the combustion gas are alike or nearly alike under the same conditions of temperature and pressure, the rotor and the fixed and movable blades of the turbineTl canbe identical The installations according to the invention "fully-exploit the possibilities provided by the fact "that the turbines Tl; T2, T3 and'T l are identical except in the formation and arrangement "of the inlet and outlet gas orifices.

"When the specific volumes of the gas-A andxthe combustion air in the compressors Cl :and C2 are similar these compressors may have similar compressors and the turbines leads to a considerable simplification 'in the tresearch, for the design and construction ofthe component parts 'and considerably reduces the numberof essential spare parts, with the result that the-cost of manufacture ,and maintenance Sis, considerably .50 with the corresponding-elements common to the turbines T2, T3 and T4.

4 reduced. The reduced obstructiveness of the installation according to the invention arises from the fact that it is possible to arrange the various parts in a small space owing to the fact that the number of compression and expansion apparatus are grouped intoindepen'dent lines of shafts.

The flexibility of operation of the installation according to the invention stems from the great variety in the conditions of operation which are .madepossible by the optional regulation in the speeds of the two "lines of shafts and of the temperature and pressure of the gas A produced. The simplicity of operation of the installation according to the invention arises directly from "the fact that all operations for the regulation or variation of the operating conditions are con- ;trolledonly by three separate devices SI, S2 and S3. Several particularly advantageous embodiments according to the invention are possible and the characteristics of these are mentioned below.

One embodiment comprises compressors Cl and C2 :having identical centrifugal rotor wheels preferably of a type made in large numbers, for example, aviation gas turbines.

.By way of example but not limitation Fig. 2 illustrates diagrammatically a compressor rotor according to this-particular embodiment of this invention. The :rotor comprises three identical double entry centrifugal wheels I9, 20 and 2! mounted on a common spindle a. The gas A enters the outer wheels [9 and .20 byzthe inlets to these wheels. .The gas Aleaving .thewheel l9 after.compressiontherein passes .to a diffuser and eventually .to .an intermediate cooler ithis apparatus ';may :be ;of .any .known type) and is then :led to the entryof the central wheel 20 adjacent tothe wheell9. The gas A leaving :the wheel 2| after compression therein passes to .a diffuser and eventually to an intermediate cooler .(thisapparatus can be of any known type) and is then led to the entry of the central wheel 20 adjacent the wheel 2|.

The gas A leaving the wheel 20 passes to a diffusor from which it is directed towards the discharge'end of the compressor.

When the fuel used in the installation according to the invention is a known combustible liquid the compressor C2 is a compressor for combustive air identical with the compressorCl for the gasA except for the formation and arrangement of the inlet and outlet orifices. In this case the apparatus C3 will'be a pump for combustible liquid coupled in the line of shafts II.

When the fuel used in an installation according to the invention is a weak gas, for example, blast furnace gas, the apparatus C3 and the compressor C2 are combined in asingle compressor C2 identical with Cl. .In this later case the identical rotors of the compressors Cl and 02 can be composed, for example, of an odd number of centrifugal Wheels including a centraldoubleentry wheel and a median wall.

Byway of example Fig. 3 illustrates a rotor of this later type. The circuit for the gas A in the rotor illustrated in Fig. 3 is identical with the circuitfor gas A .in the ;rotor illustrated in Fig. 2. The combustive air circuit in the rotor illustrated in Fig. 3.is asfollows: the combustive air enters in the .outerwheel .22 by eachof its inlets, the combustive air leaves the wheel 22 after compression therein and passes into a diffuser and eventually into an intermediate cooler (this apparatus can be of any knowntype) and it-is then led to the inlet 25 of the central wheeli2-3 adjacent .the wheel 22. The combustive air which leaves the wheel 23 at 26 passes into a diffuser 21 into which it is directed towards the delivery end. The circuit for fuel gas in the rotor as illustrated in Fig. 3 is as follows: the combustible gas enters in the outer wheel 24 from each of its inlets, the fuel gas leaving the wheel 24 after compression therein passes to a diffuser and eventually to an intermediate cooler (this apparatus can be of any known type) and is then led to the inlet 29 of the central wheel 23 adjacent the wheel 24. The fuel gas leaving the wheel 23 at 30 then passes into a diffuser 3| into which it is directed towards the delivery end. It may be observed that the combustive air and the fuel gas remain separate in the compressor C2, of which the rotor is illustrated in Fig. 3, except in the very small space between the median wall of the wheel 23 and the separation wall of the diffusers 21 and 3|. The smallness of this space checks any appreciable mixing of the air and gas.

When an installation according to the invention comprises a single compressor C2 for combustive air and weak gas the variation in the combustion temperature controlled by the regulator SI is obtained by admitting to the weak gas, upstream of the first stage of the compressor C2, of variable amounts of burnt gases previously withdrawn at their escape to the atmosphere and previously cooled to about ambient temperature in a cooler of any known type. By way of example but not limitation Fig. 4 illustrates diagrammatically an installation for the production of a hot blast for a blast furnace, constructed according to the invention, the fuel used being blast furnace gas. In the installation illustrated in Fig. 4, coolers of any known type, for example the water circulation type, are arranged between the points 2 and 3,2 and 3, l0 and II, It! and II, and 36 of the circuit. The regulator S2 controls the valve V3 for admitting through the conduit 34 and upstream of the compressor C2 cooled burnt gases to the weak gas, C2 thereby to obtain a regulation of the combustion temperature. The compressor Cl is of the type illustrated in Fig. 2 and the compressor C2 is of the type illustrated in Fig. 3. The other components of the installation are similar to those shown in Fig. 1.

By way of example the characteristics of this installation are as follows:

Actual pressures (atmos- C. pheres) Points pera- Lbs/sec.

our."

Air Burnt gas Total isentropie yield of all the apparatus: 0.8.

6 What I claim is: In an apparatus, for use in the production of hot gas at a desired rate and temperature and pressure, in combination: two rotatable shafts spaced from each other; the first of said two shafts comprising a first compressor, a first turbine, and a second turbine, keyed to said first shaft for rotation therewith; the second of said rotatable shafts comprising compressor means, a third turbine, and a fourth turbine, keyed to said second shaft for rotation therewith; a first heat exchanger, a second heat exchanger, a third heat exchanger, and a combustion chamber structure operatively disposed for turbine and compressor connection; said first compressor of said first shaft and said first and second heat exchangers and said second turbine of said first shaft and said third heat exchanger being interconnected in series forming a circuit for the compression and heating and expansion and reheating of said gas; and compressor means of said second shaft and said combustion chamber and said third heat exchanger and said second heat exchanger and said fourth turbine of said second shaft being interconnected in series forming a part of a combustion gas circuit for a first combustion gas expansion, said first turbine of said first shaft and said third turbine of said second shaft being interconnected in parallel to said fourth turbine of said second shaft and forming a succeeding part of said combustion gas circuit for a second combustion gas expansion substantially equally apportioned between said shafts, and said first heat exchanger being interconnected to said first and third turbine completing said combustion gas circuit for the production and expansion and heat exchange of a combustion gas; all of said turbines having substantially identical structural dimensions and construction, and said first compressor and at least a portion of said compressor means having substantially identical structural dimensions and construction, whereby the outputs by weight of said hot gas and of said combustion gas will be substantially equal during normal operation.

PIERRE EDMOND JULES MARIE MALDAGUE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,422,131 Ruegg June 10, 1947 2,457,594 Nettel et al. Dec. 28, 1948 2,478,504 Ruegg Aug. 9, 1949 2,539,744 Keller Jan. 30, 1951 FOREIGN PATENTS Number Country Date 590,222 Great Britain July 11, 1947 

